Ultrasensitive Determination of Selenium and Arsenic by Modified Helium Atmospheric Pressure Glow Discharge Optical Emission Spectrometry Coupled with Hydride Generation.

We herein report the development of a compact and robust optical emission spectrometry (OES)-based technique for the ultrasensitive determination of Se and As utilizing hydride generation (HG) as the sampling technique and direct-current atmospheric pressure glow discharge in He (APGD) as the radiation source. The emission sensitivities of 50 ng mL-1 Se and As in the newly designed HG-APGD were enhanced more than 3-fold by constraining the spatial volume between two hollow-tube APGD electrodes, and the stability was significantly improved. The developed technique achieved Se and As detection limits of 0.13 and 0.087 ng mL-1, respectively, with the corresponding relative standard deviations at analyte concentrations of 50 ng mL-1 being <0.5% in both cases. Moreover, the HG-APGD-OES procedure was advantageous in that it exhibited a low power consumption (<17 W) and a low gas consumption (<100 mL min-1). Its accuracy and practicality were also demonstrated by the determination of GBW10024 (scallop) and GBW07381 (stream sediments) certified reference materials and mice blood samples. The results showed good agreement with the certified values and values obtained using inductively coupled plasma-mass spectrometry.